Dust collectors, as articles for daily use, are widely used for the cleaning of indoor and outdoor. A dust collector is a cleaning appliance, in which air negative pressure is created in a sealed housing, by using vanes to rotate at a high speed with a motor, for sucking dust into a dust collecting device and discharging filtered air from a fan at an extremely high speed. The dust collectors are classified into dry type dust collectors and wet-dry type dust collectors according to their functions. The dry type dust collectors generally include dust-bag type dust collectors and machine-body type dust collectors. The dust collectors may be classified, according to their shapes, into horizontal dust collectors, vertical dust collectors and handheld dust collectors, and so on. The handheld dust collectors are convenient for cleaning articles such as a wall surface, a sofa, a windowsill, a desktop and an electrical appliance.
A dust-air separation mode of a dust collecting part of a conventional handheld dust collector is generally of a first-stage centrifugal separation mode or a dust-bag filtering mode, and both of the two filtering modes have a low filtering efficiency and are apt to cause blockage.
A conventional two-stage separation type machine body generally includes a two-stage dust-air separation structure. A first-stage structure is used for filtering large dirt in air, and a second-stage structure is used for separating and collecting small dirt such as dust particles. In the conventional two-stage dust-air separation structure, a second-stage cyclone is generally formed by cooperation between a cover plate for a filter of the machine body and a cyclone body having several cyclone openings. Such a structure requires a lot of parts and components, and further involves relatively more and complicated molds and assembly processes. Further, each link is difficult to be sealed, and it is apt to occur air leakage and dust leakage phenomena, which adversely affects comprehensive performance of the whole machine.
Chinese Patent CN 200520102558.7 discloses an integrated two-stage separation type machine body. The structure of the machine body is laid out in an axial direction, in which an inner tube and an outer tube of a dust removal device are axially arranged for separating the dust from the air. However, in such a design, there are a large number of components, and, a second-stage dust barrel, since being arranged in a first-stage dust barrel, occupies space of the first-stage dust barrel, which occupies a most dust-collecting volume of the machine body, and causes a limited dust storage space and affected dust suction effect. Moreover, an air return area of the second-stage dust barrel is small, resulting in a low air volume of the whole machine. Further, the structure of this two-stage dust-air separation type machine body requires the machine body to have a relatively large height and a relatively large volume, and the shape of the machine body is not applicable for a portable handheld dust collector, and the application scope thereof is limited. Also, since the handheld dust collector has great flexibility and has its orientation changed at any time at work, the dust in the conventional machine body is prone to back flow.
In view of the above issues, it is necessary to propose a novel handheld dust collector having a spiral two-stage tornado dust-air separation structure, which reduces the number of parts of the structure, simplifies assembly processes, improves the comprehensive performance of the whole machine and also effectively reduces the space of the machine body occupied by the two-stage dust-air separation structure, thereby achieving a maximum dust storage volume, improving dust collection efficiency and preventing the dust from back flowing effectively.